book keeping on ignore files
fixing conflicts for merge with hadley

Merge remote-tracking branch 'hadley/master'

Conflicts:
	.gitignore
Merge remote-tracking branch 'hadley/master'
tests put into test-parsers.R
allows timezone to be propogated from .local_parse()
Merge branch 'issue_178' of https://github.com/vitoshka/lubridate into issue_178
proposed solution to mixed-format case
commented modifications to .strptime()
took out my first fix for #179, restored vitoshka's fix for #177
with_tz only when in ISO8601 format and tz != UTC

Also honor tz = "" as current user's timezone.