core: Use name groups for ISO tools

Use java7 feature of name groups when matching cluster
and tool version for ISO files in ISO domain.

Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>
Change-Id: Id19888eee7c1afc7489af5208b6cddd2376d74a3
core: Use static memeber to get ISO regex pattern.

Use final static member instead recalculating the string over and over
again in a method.

Change-Id: Iffbdd09373916206d997132bc01fc02179d01973
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>