Update Google-API-Client.podspec

Added Common subspec for shared files (contains only GTLDefines.h)
[Add] LAWalkthrough 1.0.0
Merge pull request #1835 from larryaasen/master

[Add] LAWalkthrough 1.0.0
Wrong exclusion
Merge branch 'master' of github.com:CocoaPods/Specs
Updating NCWeibo to version 0.1.2
[Update] DAAppsViewController 1.1.0
[Update] SGBDrillDownController (1.0.4)
[Update] Audjustable (0.0.4)
[Add] wpxmlrpc

A lightweight XML-RPC encoder/decoder for iOS and OS X.
Updated Forecastr to v0.0.2

Adds API caching.
Merge pull request #1839 from markrickert/update-forecastr

Updated Forecastr to v0.0.2
Merge pull request #1828 from zdavison/patch-1

Update Google-API-Client.podspec
[Add] ALRadial 0.1.0
[Add] EXiLE (1.0.0)
Merge pull request #1840 from jacksonh/master

[Add] ALRadial 0.1.0
[Update] adlibr (3.2.1.1)
Added DTCoreText 1.4.0
Added DTFoundation 1.2.0
Added MGPinViewController