Bumping ProxyManager dependency to 0.5.x
Removing deprecated call to `ProxyManager\Configuration#setAutoGenerateProxies()`
Uniform functionality of `write_proxy_files` and `auto_generate_proxies` (since the latter is deprecated)
Moving up code setting the proxy namespace (used internally in the config object)
Importing test from zendframework/zf2#5198 by @blanchonvincent
Always enable proxy autoloader
Removing duplicate test case
Completely dropping `auto_generate_proxies` flag (deprecated)
Removing `auto_generate_proxies` flag from tests
remove dependency on stdlib package

This commit removes the dependency on the Stdlib package so that the Dom package can be used completely standalone. It does so by extending DOMXpath to wrap each raised error with an ErrorException with logic similar to that used in Stdlib ErrorHandler.
use end() instead of convoluted count()
add back vendor/.gitignore, thanks @samsonasik
remove TYPE_SELECT deprecated Constant that marked will go away in 2.1
Merge pull request #5865 from pmjones/develop

remove dependency on stdlib package
[#5865] Fix filesystem filename case

- s/DOMXpath/DOMXPath/ so that filename and class name match (fixes
  failure in Zend\Dom\Document\Query test)
[#5865] Added note to README.md
Merge branch 'feature/5865' into develop

Close #5865
Merge pull request #5869
Merge pull request #5858 from Ocramius/hotfix/proxy-auto-generation

Deprecate Proxy auto-generation. Close #5198