FLUID-5327: Converting ChangeApplier doc

Converted http://wiki.fluidproject.org/display/docs/ChangeApplier+API to a markdown page.
FLUID-5327: Change syntax for italics

Using _ instead of * for italics to avoid conflicts and confusion with ** for bold.
FLUID-5362: Starting to port the Infusion Event System docs.
FLUID-5362: Improving styling in Infusion Event System docs.
FLUID-5362: Added IoCSS.md
FLUID-5362: Adding Content to Infusion Event System docs.
FLUID-5362: Replaced <code> elements with single backticks.
FLUID-5362: Adding the remaining content to the Infusion Event System docs.
FLUID-5362: Styling tweaks to Infusion Event System docs.
Merge branch 'master' into FLUID-5327
FLUID-5327: Updated based on code review.

Added more inline codifying.
Merge remote-tracking branch 'cindy/FLUID-5362'
Merge branch 'master' into FLUID-5327
Merge branch 'master' into FLUID-5362