Fix exception that occurs with libc++ regex engine (yhirose#368)

The regex that parses header lines potentially causes an unlimited
amount of backtracking, which can cause an exception in the libc++ regex
engine.

The exception that occurs looks like this and is identical to the
message of the exception fixed in
yhirose#280:

	libc++abi.dylib: terminating with uncaught exception of type
	std::__1::regex_error: The complexity of an attempted match
	against a regular expression exceeded a pre-set level.

This commit eliminates the problematic backtracking.

Support for deflate compression (yhirose#360)

Update README

Fix yhirose#349

Added a contributor to README

Updated README

Updated README

V0.5.0

Code cleanup

Fix yhirose#289: Fixed build problem with Visual C++