* fixed bug in vasprintf_append() causing the input string to stay unchanged
* fixed possible memleak in vasprintf_append() in case realloc fails
Merge pull request #124 from MarcelNehring/fg_string

Fixed bugs in vasprintf_append()
Added checks to ensure provided directory for dump files is valid and correctly formatted, defaults to CWD if not provided
fixed possible crash in case dump thread is canceled and cleanup function is called twice
fixed possible crash in case dump thread is canceled and remove_flow() is called before dump thread actually terminated
fixed that uninit_flow() invalidates all existing pointers to flows following the one in question
[Code Style] Added comments to option struct
Added ap_free call to end of programs and made arg parser static in controller+daemon.

This makes sure the arg parser lives as long as the program.
[Code Style] Added comments to parsing functions + Adapted function headers
Added function ap_is_used to check if option was specified on cmdline.
Added macro for unified parsing error messages.
[Code Style] Moved Brackets.
Added parameter "opt_string" to parsing functions.
Unified parsing using macro "PARSE_ERR". Also adapted "sscanf" calls.
[Code Style] Broke some lines.
Combined -h and --help option in controller.

-h can now use optional argument too (without blank after -h).
Changed -v --version output.

Added two macros for version output to common.h to be used in all other files.
Merge pull request #126 from MarcelNehring/squash

Partially fixed tcpdumping (option -M)
Merge pull request #127 from erzb5e6f65/next2

Cleanup&Unify controller parsing