Update to version 1.7

Changelog:
Much of code cleanup and factorization overall.

pcheck:

• Add flavors support
• Print port's flavors after portlint check

pclean, pcommit:

• Update ports cleanup code to remove flavored workdirs also

pfind:

• Optimize exact search

plist-sort:

• Fix variable names clashes in awk snippets leading to incorrect plists

reinplace-check:

• Add support for flavors and multiple pathfix patterns

upgrade-ports:

• Detect package origin change, set new origin and rebuild all reverse dependencies
• Improved pkg to port conversion, fixes old pre-flavors packages upgrades
• Don't offer to rebuild or install ports that already failed
• Fix install phase error detection
• Split rebuild into new phases: stage, deinstall and install This fixes some ports building something during stage operation, mainly Qt 4/5 ports
• Configure all ports while using preinstall -c