Content: New transmission type, CVT

Added Continuously Variable Transmissions
-Automatically changes ratio of first gear to keep input rpm at a target
rpm.
-Has a discrete second gear for reversing.
-Limited torque ratings, and heavier than an equivalent manual
transmission would be.
Content: ACF Expression2 Extension

Added some E2 functions relating to various ACF entities.
-Search "acf" in e2helper for a complete list and description of
functions.
-Includes the convar "sbox_acf_e2restrictinfo" that restricts certain
functions (generally those that return sensitive data) to usage on owned
entities, preventing abuse during battles. Defaults to 1 (restricted).
-Functions that change values, e.g. gearbox shifting, are permanently
restricted to owned entities.
Content: Engine Sounds

Added some sounds for various engine types.
Changed version number for Fervidusletum's pull request.
And again.
E2 Extension: Engine info checks

Added restriction checks to some engine functions.
E2 Extension: Gearbox info checks

Derp, should have added these in while I was at it.
Fixed typo in CVT
Updating version for Fervidusletum's new CVTs.
Fix: Ammo crate explosiveness

Ammo crate explosion power is now determined by how much explosive
content is inside the crate, rather than purely on ammo count.
Generally, expect less boom from smaller rounds, and more boom from big
rounds.
Updated version number for Fervidusletum's new ACF E2 extension.
Updated version number for Fervidusletum's ammo explosion fix (explosions based on explosive content).
Fix: Massive explosion from multiple ammo caches

Had overlooked the multiple ammo crate explosions, they were still based
solely on ammo.
Changed CVT behaviour, far less annoying sound

CVT now has a target rpm range, instead of a single rpm.  This lets the
engine rpm vary with speed, so you don't have to listen to a single
monotonous tone for 5 minutes straight.  Also results in a slightly
faster response time.
Changed version number for Fervidusletum CVT + Ammo fixes.