Bug fix: Proper implementation of CURL write function

CURL write function does not process whole response at once, but in chunks.
Implementing response data concatenation was required. Thanks to juef for
reporting and assistance during debugging.
Config file parser; ERE-based patterns

Notable changes:
 - support for reading/writing standard key-value configuration file
 - POSIX ERE-based patterns for parsing file name
 - code restructuring with minor refactoring