fixed a couple of bugs in the shell scripts

[muzso]

Some of the fixed issues:

• variables were used as commandline arguments without being in quotes and with the possibility of containing whitespaces (where the contents of the variable would be split into multiple commandline arguments upon expansion)
• indentation was not coherent (both tabs and spaces were used)
• filepathes can contain whitespace characters (including newlines) and some of the scripts didn't account for this
• build.sh failed with unbound variable if it's last commandline argument was a "--"
• a couple of typos