BUG: Fix bugs with CR removal in SCIFIOImageIO::WaitForNewLines

Most importantly, this fixes an infinite loop, as the variable
"backslashRIndex" is never updated inside the old while loop.

Additionally, the call to std::string::erase must be made with 2
arguments, or the entire remaining length of the string is erased.
Merge pull request #7 from brianhelba/Read-Infinite-Loop

BUG: Fix bugs with CR removal in SCIFIOImageIO::WaitForNewLines