Fixing two failing tests
Suppressing warnings when unable to parse XML. Closes #602
Making clients more immutable

- Removing getConfig() and setConfig() from clients to avoid confusion around
  whether things like base_url, message_factory, etc should be able to be
  retrieved from getConfig() or modified using setConfig().
- Adding getDefaults() and setDefaultValue() to customize default request
  options of a client.
- Updating Url class to check if a scheme and host are set before adding
  ":" and "//". This allows empty Url (e.g., "") to be serialized as "".
- Removing dead code from Url class.
- Adding a functions.php function for get_path and set_path so that these
  functions can be used on regular PHP arrays. Collection now proxies to these
  functions when Collection::(get|set)Path() is called.
- Resolves #599.
Cleaning up
fix some typos on master guzzle
Merge pull request #604 from cordoval/fix-typos

some fixes
Renaming getDefaults() to getDefaultValue()
Merge pull request #603 from guzzle/immutable_configs

Making clients more immutable
Making the test server static and adding Makefile
Updating gitignore
Adding perf test to makefile
Making it so request options are described more in-depth in the docs
Ensuring the mock adapter reads the request body and emits a headers event
Removing empty line
Adding progress subscriber to the docs
Using .PHONY instead
Adding the ability to control the curl_multi select timeout using an envrionment variable
Adding support for HTTP_PROXY and HTTPS_PROXY
Renaming (g|s)etDefaultValue() to (g|s)etDefaultOption()
Adding testing docs