ports-mgmt/synth: Yet another release candidate

Unfortunately, there's been a bit too much change since 0.99_6 to
confidently release version 1.00, so another release candidate is
necessary. Both new features and bug fixes were added.

New features:

• Provide ability to define environment variables in a profile (/usr/local/etc/synth/<profile>-environment)
• Support fetching by proxy using these environment variables
• Add zsh and bash completion scripts
• Accept port origins with trailing file separators (so people using completion scripts don't have to backtrack to remove them)
• In text (non-curses) mode, output the current package build tally every 200 seconds (approximately)

Bug fixes:

• Fix support for system roots that don't match host (e.g. ARCH, OSRELEASE, OSVERSION, etc
• Fix ABI check for system roots that don't match host
• Remove effect of system /etc/make.conf (originally seen when MAKE_JOBS_NUMBER was defined there and disabled synth)