Add log_debug function, add to each clines.append.
Mod clines.append, use str() to concat with log_debug.
Add command line params: keep_logs, log_dir; mod log_debug to log_output.
Add TODO: allow option file for cmdline args
Logs: repaired outstream handle.
corrected typo: variable 'usage' should be 'Usage'
Added citation information as well as dependency versions required to run the pipeline
Within the function 'build_blast_input': 'primer.forward.seq' and 'primer.reverse.seq' were updated to 'primer.forward_seq' 'primer.reverse_seq' respectively
updated / reworded section text
added basic use information
fixed typo within 'basic use' section
fixed typo within 'basic use' section
fixed typo within 'basic use' section
added BLAST+ to DEPENDENCIES section
fixed typo within 'basic use' section
 Within the 'parse_blast' function: updated split character from '_' to '_primer_'
fixed typos, rewored some text, added 'FURTHER INFORMATION' section
Merge branch 'master' of https://github.com/mikerobeson/find_differential_primers into mikerobeson-master

Conflicts:
	find_differential_primers.py
	utils/stitch_six_frame_stops.py

Fixed conflicts over case of 'Usage' vs 'usage' in the option parser, and the issue over primer.forward_seq and primer.forward.seq
Added try-except catch for parsing empty BLAST files. Old behaviour was that script would crash if
BLAST file was empty, new behaviour is that the parsing error is logged.
Added second citation and contributor list to README