improved phar compression
improved phar compression

there are two different ways to compress a phar file: for each file inside
the phar one after one or for all files at once.

the all file at once method can trigger a runtime exception if not enough
file handles for open files are available - but it is much faster.

both variants have been extracted into a method of it's own and when the
all files at once method fails, the file-by-file method is taken.

the dead code has been removed as well.

pocallaghan/n98-magerun,bluec/n98-magerun,twslade/n98-magerun,adam-paterson/n98-magerun,TriplesenseReply/n98-magerun,chadbean/n98-magerun,kojiromike/n98-magerun,tkn98/n98-magerun,chadbean/n98-magerun,pocallaghan/n98-magerun,tkn98/n98-magerun,bluec/n98-magerun,kojiromike/n98-magerun,TriplesenseReply/n98-magerun,adam-paterson/n98-magerun,adam-paterson/n98-magerun,oasisfleeting/n98-magerun,EmPeWe/n98-magerun,EmPeWe/n98-magerun,EmPeWe/n98-magerun,kojiromike/n98-magerun,twslade/n98-magerun,chadbean/n98-magerun,tkn98/n98-magerun,therouv/n98-magerun,bluec/n98-magerun,therouv/n98-magerun,pocallaghan/n98-magerun,oasisfleeting/n98-magerun,TriplesenseReply/n98-magerun,twslade/n98-magerun,oasisfleeting/n98-magerun