Add curve module

This breaks quantity tests - due to the addition of Percentage
Will fix these later
Add eventstore
Add calendarstore

this compiles but tests won't run due to the classpath depending on both
log4j-over-slf4j and slf4j-log4j12
Add kafka start/stop scripts
Maker config

evcel can now run either as an SBT or a maker project
merge Percentage fixes from 'core'