Remove SVN keywords from codebase

[stephanr]

The first commit was generated by replacing the results of this regex with nothing:

^//\s*\$HeadURL[^\r\n]+[\r\n]+

The second commit was generated by replacing the results of this regex with nothing:

^\s+\*\s+@version\s+\$Revision[^\r\n]+[\r\n]+
^\s+\*\s+@author last edited by: \$Author[^\r\n]+[\r\n]+
^\s+\*\s+@version. \$Revision\$, \$Date\$[\r\n]+

The rest was manually done by going through who matched:

\$(Date|Revision|Author|HeadURL|Id|Header|Rev)

closes #1502