fix bug reported by issue59 and increase version number from 1.7.2.3 …

…to 1.7.3

remove bug causing error 'raworfhits referenced before assignment' in…

… rare cases

add code to remove temporary files

Merge branch 'v1.7.2.2'

add .csv and .tsv result files

update readme

Merge branch 'v1.7.2'

update constants.py

update readme

Merge branch 'v1.7'