Add flag to configure the meaning of Hit.Partial

[killy971]

At the moment, coveralls.io api to describe code coverage is rather simple: it is based on the number of hits for each line, meaning meaning that the line was never hit.

hpc, on its side, provide a very precise coverage report which supports partial-line coverage. Therefore, the following convention is currently used by hpc-coveralls to express line coverage data into line hit counts:

• 0 : the line is never hit,
• 1 : the line is partially covered,
• 2 : the line is fully covered.

This change will introduce a command line argument to swtich to another coverage data conversion mode with the following convention:

• the line is never hit : 0,
• the line is partially covered : 0,
• the line is fully covered : 1.

[killy971]

Feature branch: partial-coverage-configuration