Remove gitmodules

Integrate api and lang into core
#561 Solves "The coremod does not have a MCVersion annotation" message
Merge pull request #543 from thatsIch/e-remove-submodules

Remove gitmodules
Added MIT license to all api files
Merged api and lang READMEs
Merge pull request #587 from yueh/readme

Closes #584 Merged api and lang READMEs
Merge pull request #588 from yueh/api-license

Added MIT license to all api files
Update readme to reflect the api and lang repo merges

Removed recursive statement when cloning
Updated the order for building 
Clarified instruction for setup
Added information to squash commits when contributing
Format the dependencies
Added language code reference for quick look-up
Bump channel to beta
Closes #593 Updating RF Integration to use version 1.7.10R1.0.2

The new update contained a split of the IEnergyHandler into the IEnergyReceiver and IEnergyProvider.
Since all tiles in AE2 are basically IEnergyReceivers we use them and changed the detection of opposing tile entities from IEnergyHandler to IEnergyReceiver
Merge pull request #595 from thatsIch/e-593-newrfapi

Closes #593 Updating RF Integration to use version 1.7.10R1.0.2
More precise javadoc of IStorageCell

Reflects the internal implementation of StorageCells
Merge pull request #562 from thatsIch/e-561-mcversion

Solves #561 "The coremod does not have a MCVersion annotation" message
Uses the canonial names of the classes instead of hard coded strings