added flag and functionality to suppress output, just return non-zero if URLs differ.
pulled in master README.md
Merge branch 'quiet_mode'

Conflicts:
	url_diff.py
update README with new help text.
rewrote method to parse hostnames, no longer check hostname validity as that is a non-goal of this tool.
add back character deleted during reformatting.
updated and added to some docstrings.
skip param diff if param dicts are equal.
store url param token in full with empty value if now equals sign.
skip falsey strings when parsing URL parameter tokens.
Merge branch 'master' of https://github.com/google/url_diff
skip param diff if param dicts are equal.
Merge branch 'avoid_diff_if_equal' of https://github.com/google/url_diff into avoid_diff_if_equal
make right URL (second positional arg) optional. now url_diff can be used to enumerate a single URL which I think is more readable.
new todo
Merge branch 'master' into avoid_diff_if_equal
Update readme for optional right URL behavior.