chore: simplify gitflow.c
add exec_shell_command basic skeleton
add dummy shell script
make definitions extern
chore: change 'char const' to 'const char'
add prepare_command and exec_command functions
update run_command file functions
rename to feature.sh
bugfix: remove -c flag from shell command
update gitflow.c to modify args array
Merge pull request #1 from ajthor/run_command

run shell commands from program