Added new commands:

• help - shows info about commands
• set - allows to set the value of a configured placeholder (will NOT be persisted!).

Example with a configured placeholder "rank-elite":

rank-elite=Elite

Change dynamically with

/cpapi set rank-elite SuperDuper

Just a re-build to support older MC server versions. Has been tested with a Spigot 1.8 server, and a Paper 1.18.1 server. I just assume that it also works with every version in between.

Fixes a potential infinite loop in the configuration processing if a line contains a "${" prefix, but no closing "}" bracket.