exit from subshell; simplify checks for binaries

[ollo22]

In revancify / checkDependencies(),

installdependencies || (echo "Dependencies not installed !!" && exit 1)

does not do what the author probably intended. The exit is contained in a subshell, so it basically does nothing. I've fixed this in https://github.com/decipher3114/Revancify/pull/24/commits/250523b1956cfc16e7c96698a384529f9df6fa79; I've also simplified the overly complex check for the existence of various binaries (using, ironically, also an exit from a subshell — but the exit code is then checked).