[python-bindings] Added support for iterating over a function's basic blocks, dumping/getting names of those bb, f/w iteration.

Tests are included.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190473 91177308-0d34-0410-b5e6-96231b3b80d8
[python-bindings] Added support for iterating over a basic blocks instructions, getting their name/dumping them, f/b iteration.

Tests are included.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190475 91177308-0d34-0410-b5e6-96231b3b80d8
[python-bindings] Added support for getting/setting operands of values and getting the number of operands of a value.

Also in the process did some cleanups for BasicBlock.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190477 91177308-0d34-0410-b5e6-96231b3b80d8