Some corrections

[jsaintvanne]

Differents corrections :

• when you run it with few files and obtain no matching between samples, there is now an error message No results for these files... (Problem when files haven't any result workflow4metabolomics/metaMS#37)
• change sapply into lapply because with 2 files there were an error because sapply and unlist didn't make a list and arguments hadn't the same length... It looks that works like this !
• revert new.annotations and annotations to have no error when the first result has 0 row (has mentionned here Problem when first annotation has no match in DB workflow4metabolomics/metaMS#36)
• Add verification of matrix because when we have columns with the same length we obtain a matrix whereas we would like a list... (Error with CDF and DB workflow4metabolomics/metaMS#39)

[jsaintvanne]

@yguitton je retrouve une erreur lorsque j'enlève dans matcheSamples2Samples ce qu'on disait, donc la PR est bien comme ça ! :)