Merge branch 'horizontal_fix' into 'master'

Fixes to horizontal spring collision

Fixed various issues arising from collision with exclusively horizontal springs. Thamks to @Inuyasha for the heads up! Of note:

* If you hold down your jump button whilst jumping into it, you no longer immediately use your ability.
* Characters with (CA_DOUBLEJUMP && CA2_MULTIABILITY) or CA_FLOAT or CA_HOVER no longer lose track of their jump count.

Also:

* Upped the strength of info.c's red and yellow horizontal springs.

See merge request !41