PulsarCrossCorr_v2: added functionality to keep candidates above SNR threshold and to sort toplist
XLALParseDataFile(): allow passing of *file-contents* directly instead of filename

- by passing a string like "{ file-contents }" instead of a file-path,
- This is useful to allow ascii-file user inputs to be transparently
  passed as filenames or direct contents
- refs #1537