Added description for Callables example
Added description for Executors example
Added description for Enhanced Intrinsic Lock example
Added description for Read-Write Lock example
Added description for Semaphore Lock example
Minor correction on description of Semaphore Lock example
Updated the ReadWrite Lock description to be a bit more detailed
Updated the Callable description to be a bit more detailed
Minor cosmetic change to Callable description
Updated the Intrinsic Lock description to be a bit more detailed
Minor enhancements to the detailed description of the Callable example
Merge branch 'master' into develop