Putting all the standard tool options into a "Generic" category.

Summary:
This puts all the options that CommandLine.cpp implements into a category so that the APIs to hide options can not hide based on the generic category instead of string matching a partial list of argument strings.

This patch is pretty simple and straight forward but it does impact the -help output of all tools using cl::opt. Specifically the options implemented in CommandLine.cpp (help, help-list, help-hidden, help-list-hidden, print-options, print-all-options, version) are all grouped together into an Option category, and these options are never hidden by the cl::HideUnrelatedOptions API.

Reviewers: dexonsmith, chandlerc, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7150

llvm-svn: 227093