Telegraf support for built-in windows service.

Updated windows dependencies

Updated the windows dependencies so that the versions matched the
dependencies for Mac OS and Linux. Additionally added some that were
complained about being missing at compile time.

Incorporated kardianos/service for management

Incorporated the library github.com/kardianos/service to manage the
service on the various platforms (including Windows). This required an
alternate main function.

The original main function was renamed to reloadLoop (as that is what
the main loop in it does) (it also got a couple of parameters). The
service management library calls it as the main body of the program.

Merged service.go into telegraf.go

Due to compilation issues on Windows, moved the code from service.go
into telegraf.go and removed service.go entirely.

Updated dependencies and fixed Windows service

Updated the dependencies so that it builds properly on Windows,
additionally, fixed the registered command for starting it as
a service (needed to add the config file option). This currently
standardizes it as a C:\telegraf\telegraf.conf on Windows.

Added dependency for github.com/kardianos/service

Removed the common dependencies from _windows file

Removed all the common dependencies from the Godeps_windows file and
modified Makefile to load Godeps and then Godeps_windows when building
for Windows. This should reduce problems caused by the Godeps_windows
file being forgotten when updating dependencies.

Updated CHANGELOG.md with changes

Ran `go fmt ./...` to format code

Removed service library on all but Windows

The service library [kardianos/service](github.com/kardianos/service)
has been disabled on all platforms but windows, as there is already
existing infrastructure for other platforms.

Removed the dependency line for itself

It appears that gdm accidentally added the project itself to the
dependency list. This caused the dependency restoration to select an
earlier version of the project during build.

This only affected windows.
This only affected builds after 020b2c70

Updated documentation for Windows Service

Removed the documentation about using NSSM and added documentation on
installing telegraf directly as a Windows Service.

Added license info for kardianos/service

Added the license information for github.com/kardianos/service which is
licensed under the ZLib license, although that name is never mentioned
the license text matches word for word.

Changed the Windows Config file default location

Updated the default location of the configuration file on Windows from
C:\telegraf\telegraf.conf to C:\Program Files\Telegraf\telegraf.conf.
With this change includes updating the directions, including directing
that the executable be put into that same directory. Additionally, as
noted in the instructions, the location of the config file for the
service may be changed by specifying the location with the `-config`
flag at install time.

Fixed bug - Wrong data type: svcConfig

svcConfig service.Config => svcConfig *service.Config
(It needed to be a pointer)

Godeps

@@ -29,6 +29,8 @@ github.com/hpcloud/tail b2940955ab8b26e19d43a43c4da0475dd81bdb56
 github.com/influxdata/config b79f6829346b8d6e78ba73544b1e1038f1f1c9da
 github.com/influxdata/influxdb e094138084855d444195b252314dfee9eae34cab
 github.com/influxdata/toml af4df43894b16e3fd2b788d01bd27ad0776ef2d0
+github.com/kardianos/osext 29ae4ffbc9a6fe9fb2bc5029050ce6996ea1d3bc
+github.com/kardianos/service 5e335590050d6d00f3aa270217d288dda1c94d0a
 github.com/klauspost/crc32 19b0b332c9e4516a6370a0456e6182c3b5036720
 github.com/lib/pq e182dc4027e2ded4b19396d638610f2653295f36
 github.com/matttproud/golang_protobuf_extensions d0c3fe89de86839aecf2e0579c40ba3bb336a453