Revert "make mutual push-resistant unit collisions more like 0.82.x (smoth's issue)"

This reverts commit f4577b6b5efa89098139d709164d701dbfa1dade.
Revert "QTPFS: fix a large part of #3423"

This reverts commit 443debb963a6688cd3d9b2b0fe42da05c2cab94e.
Revert "fix #3498, unit double click select units of same type in view"

This reverts commit 7f3f2a8ab2a2e57679ef8e429ab110ba34cd1ecf.
Revert "un-duplicate *TreeDrawer::TreeSquareStruct"

This reverts commit e3a5c3f9e2021fe51f67f30f653725a3b0014c5e.
Revert "fix #3489 (default trees not obeying featureLoS rules)"

This reverts commit 2b23d7a15ce7906dbfedf088e71f75a5d37bbda0.
Revert "fix some cases of units getting perma-stuck (s.t. even spammed user orders cannot free them) on terrain"

This reverts commit d62c2fafea1a82ca253133aff271ad5a691b2a17.
Revert "fix bug in MoveDef::TestMoveSquare"

This reverts commit c1e605a6c2a470694e44a2c16d9ce948bdd873de.
Revert "fix #3505"

This reverts commit 9235db3fc49eeb0a661c4cf9683d3c9b6809c8e3.