Added INTTIM parsing from dada header, improved timestamping

readDada routine now also reads in dada headers to calculate INTTIM.
Moved DATE / TIME calculations into readDada and out of generateUVW.
Added phase_to_src() call in readDada(), so that a complete file is generated without having to call this manually.

Signed-off-by: Danny Price <dan@thetelegraphic.com>