main: Replaced the 'acquisition' boolean by an enumeration.

This enum specifies the program mode.
Utilities: Added a function to create a directory.
Utilities: added the prototype of the 'createDirectory' function.
Utilities: Added error checking for the 'createDirectory' function.

The function is now able to check if the directory already existed.
Unit tests: created a test case for the 'createDirectory' function.
main: replaced booleans by a single format option.

The format enumeration specifies the output format.
main: minor code maintenance.

Removed a todo, fixed output file name generation...
Utilities: fixed a permission issue in the 'createDirectory' function.

The created directory could not be used as its eXecutable flag was not
set properly.
main: fixed issues related to directory names.
Merge branch 'output_dir' into order_transmission

Conflicts:
	src/main.cpp