Fixed file encoding issue.
Added support for the NOT_NULL constraint.
Added javadoc on constraints.
Added tests for invalid contracts.
Added jar and source jar in the download folder
Update README.md
Update README.md
Merge remote-tracking branch 'official-origin/master' into shusshu-master

Conflicts:
	ProviGen/.classpath
	ProviGen/AndroidManifest.xml
	ProviGen/src/com/tjeannin/provigen/ContractHolder.java
	ProviGen/src/com/tjeannin/provigen/DatabaseField.java
	ProviGen/src/com/tjeannin/provigen/OnConflict.java
	ProviGen/src/com/tjeannin/provigen/ProviGenOpenHelper.java
	ProviGen/src/com/tjeannin/provigen/ProviGenProvider.java
	ProviGen/src/com/tjeannin/provigen/annotation/NotNull.java
	ProviGen/src/com/tjeannin/provigen/annotation/Unique.java
	ProviGenTests/src/com/tjeannin/provigen/test/constraint/NotNullConstraintProvider.java
	ProviGenTests/src/com/tjeannin/provigen/test/constraint/NotNullConstraintTest.java
	ProviGenTests/src/com/tjeannin/provigen/test/constraint/UniqueConstraintProvider.java