Implemented tab usage only for indentation (http://llvm.org/PR17363)

Summary:
Changed UseTab to be a enum with three options: Never, Always,
ForIndentation (true/false are still supported when reading .clang-format).
IndentLevel should currently be propagated correctly for all tokens, except for
block comments. Please take a look at the general idea before I start dealing
with block comments.

Reviewers: klimek, djasper

Reviewed By: klimek

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1770

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191527 91177308-0d34-0410-b5e6-96231b3b80d8
Updated clang-format style options doc.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191528 91177308-0d34-0410-b5e6-96231b3b80d8
Updated examples of UseTab option

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191529 91177308-0d34-0410-b5e6-96231b3b80d8
Added a comment and another test for the UT_ForIndentation option

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191530 91177308-0d34-0410-b5e6-96231b3b80d8
Fix the test files by removing the unnecessary -emit-llvm flag (should address Matt Beaumont-Gay's concern regarding failure on a read-only filesystem)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191531 91177308-0d34-0410-b5e6-96231b3b80d8
[analyzer] Allow pre/post-statement checkers for UnaryOperator.

Found by Arthur Yoo.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191532 91177308-0d34-0410-b5e6-96231b3b80d8