Fix cleanup when no temporary file was created
Merge pull request #26 from VaclavDedik/master

Multithreading for artifact downloads
Documentation update
Fix bad import after some refactoring
Fixed incorrect groupId assigned when building artifact list from local repository.
Follow links when walking through filesystem
Close #27: Add parametr to enable logging into a file
Close #27: Add parametr to enable logging into a file
Prepend ^ and append $ to the regular expressions created from include/exclude list so that the match is exact  - i.e. GAV org.richfaces:richfaces:4.3.1.CR1 should not match pattern org.richfaces:richfaces:4.3.1
Fixed bug with copying additions
 - $ADDITION/.* causes coping of files not only hidden but also in the parrent directory (cause .* expands to .. too)
Use prefixes generated from included list to optimize listing repositories
Documentation update
Tests tuning
Fix permitting of multi-version gavs
Tests tuning
PEP8
when list of included GAV patterns is empty, search for all
optimize listing repositories when included GAV list contains "nice" regular expresions

eg. when included GAV list contains:
  "r/org\.jboss\.as:core-.*:7\..*/"
  "r/org\.weld:.*:.*"
check only paths:
  "org/jboss/as/",
  "org/weld/"
fix typo
Small cleanup