many2many, joinForeignKey, JoinReferences support

[addshore]

Before this change, a field that defined both many2many and foreignKey would always be detected as foreignKey incorrectly. This will now be detected correctly.

In cases of a many2many reference joinForeignKey and JoinReferences will now also be used to get the field names rather than inventing them.

[survivorbat]

Hey addshore, good stuff! Could you please update the unit-tests as well to verify whether this functionality works and add a few test cases? Afterwards I'll review the changes and merge them to master for v1.0.0 :)

[addshore]

Started a WIP test, which actually goes slightly further than my usage of the library (the test has custom IDs for relations).

The query its running is

no such column: id
�[0m�[33m[0.052ms] �[34;1m[rows:0]�[0m SELECT * FROM `resource` WHERE id IN (SELECT resource_id_j FROM `middles` WHERE end_id_j IN (SELECT id FROM `end` WHERE `value` = "InfraNL"))

Which is wrong as every reference to just id should be something else.
I'm fairly new to form, so wonder if you can more easily spot my issue?

[survivorbat]

Hey addshore! Sorry for the late response, it's a busy month.

I haven't gotten a chance to run it, it seems that the code doesn't respect the custom column name you defined. My implementation is rather primitive of course, perhaps a test specifically for the many2many AND foreignkey would be a good start?