Add per-sample summary information

[laughedelic]

@rtobes define please which information has to be accumulated for each sample.

[rtobes]

Per sample:

• Number of input reads (pairs of R1 and R2)
• Number of merged reads (with FLASH)
• Number of not merged reads
• Number of assigned reads
• Number of not assigned reads

Total numbers per project (summatory of the values for each sample):

• Total number of input reads (pairs of R1 and R2) of the project
• Total number of merged reads (with FLASH)
• Total number of not merged reads
• Total number of assigned reads
• Total number of not assigned reads

All these per sample data in a unique csv file with the values for all the samples and with an additional row for the total values.

[laughedelic]

This issue only takes care of producing these numbers per sample. Totals are out of scope here.