IronPython: solution include line for License.rtf breaks builds on certain filesystems

[marcusva]

The

<MiscFiles Include="$(BaseDir)\Languages\IronPython\Public\License.rtf" />

include line in Build.IronPython.proj under Solutions/ causes the build process to break on filesystems that use case-aware file and directory names (nearly all unix-like systems). The line should be changed to the correct form

<MiscFiles Include="$(BaseDir)\Languages\IronPython\Public\License.Rtf" />