Add of archiveOldFileOnStartup parameter in FileTarget

This adds the possibility of archiving an existing log file every time
an application starts. As described/proposed in #213.
Issue 373 fixed

Added one more overload for the internal method that calls the faster
overload of LogEventInfo.Create.
add fluent log builder
fix build
Merge pull request #382 from pwelter34/master

contribute fluent log builder
Merge pull request #377 from pgatilov/master

Apply small performance patch
Merge pull request #369 from cvanbergen/issue213

Add of archiveOldFileOnStartup parameter in FileTarget
Merge branch 'umaster'