bnrmth improvements

[matebn]

hi,

thx for merging this. i was a bit unsure if the code was ready for being merged, because i'm no really an expert in grunt :-) thats why i was waiting

i plan to do 2 other features as well:

• set a max release count, so for example on the production server there is always a max of 5 deploys
• create an archive before uploading it to speed up the deployment

i will send you the PR later. please keep an eye on my code and make improvements if needed.

best regards, Matthias