The purpose of the devtools source folder was to have a place to put code that should not be included in the released jar file. However, this requirement is also met by the test source folder. The devtools source folder was a relict from before we used maven.
I also externalized the devtool settings to the properties file `src/test/resources/amidst/devtools/devtools.properties`. This file is ignored by git, however there is a commited template file. To run the devtools, copy the template and populate it with the correct values. The template also contains documentation about how the values are used.
Added tests to execute each devtool. Removed all main methods from the devtools. The tests are ignored by default since they serve as a main methods.
* download all minecraft jar and json files
* check which versions have a server and which have a client
* check which versions are compatible with the current class recognition rules
There are still a lot of issues, such as the lack of all the old layers,
left over code, and a few missing features (move to for example) But
this is a start.
Note that caching methods should not be bothered with for the moment, as
a cache directory and expiration date have not been coded.
