Added clear() to TableHandler
Merge pull request #231 from alrashedf/master

Added clear() to TableHandler
Fix two minor documentation mistakes.
Fixed the documentation of clear()
Added an entry to changes.h
Fixed indentation
Merge pull request #235 from alrashedf/master

Fixed an indentation problem
Merge pull request #232 from bangerth/doc-fixes-10

Fix two minor documentation mistakes.