SP Weapon Fixes

[ampreeT]

Continuation of #20 and #21:

Issues:

• Secondary attack on the crossbow does not fire from the center of the screen
• Secondary attack on the crossbow still plays mp sound
• Crossbow suffers from prediction issues caused by CWeapon_Crossbow::ItemPostFrame() being hooked, but this is needed currently for SP implementation
• Can initiate ironsights with 357 and crossbow while using suit zoom

[Alienmario]

• The crossbow has reduced damage (if any) to (friendly) vorts
• I'm unable to hit xen controllers's heads with crossbow alt fire

[Alienmario]

• 357 ironsights animation breaks when sprinting is toggled

[ampreeT]

• 357 ironsights animation breaks when sprinting is toggled

This also happens in singleplayer too when sv_always_run is set to 0. Is this something we want to expand further on or should we mimic Black Mesa's implementation 1:1?