Added adapter-specific exception. Added second attempt to obtain PSL …

…ignoring SSL peer. Protect PHP cache to be rewrited with an empty array in case of error.

Throwing an HTTP adapter's exception if content couldn't be fetched
Added handling of exceptions during getting PSL
Prevent writing an empty data into a cache file
(by  Alex Shu)

Merge branch 'develop'

Merge branch 'feature/next-major-version'

Merge branch 'develop'

Merge pull request jeremykendall#42 from jeremykendall/develop

v2.0.2

Corrects bad docs, updates bin/parse

Merge branch 'develop'

Adds additional IPv6 tests

Removes TODO

Adds ext-mbstring to composer.json require key