for application use dynamic load, classloader count is far more than 16

! final AbstractExecutorTtlTransformlet.doTransform method, make abstract class closed to modifications

- TTL option getter methods: isLogClassTransform, getLoggerType
- Generic option getter methods: isBooleanOptionSet

- use extension file(`META-INF/ttl.agent.transformlets`) instead of agent config
- be able to auto discovery by adding dependency jar of extension transformlets

! change package of agent related classes, prepare for open agent for extension by agent/transformlet developer

- split common_build from ttl_build
- use MVN function instead of MVN_CMD array

- no lib user runtime cost, still runtime 0-dependency
  not runtime/compile Transitive dependence
- more IDE friendly
  ensure to be able to jump to annotation class(edu.umd.cs.findbugs.annotations.NonNull, etc)
  when user browse source code in IDE

use project.build.finalName instead of ${project.artifactId}-${project.version}

more info see:

- http://maven.apache.org/pom.html#BaseBuild_Element
- https://stackoverflow.com/questions/20859734/what-is-the-value-of-project-build-finalname
- https://stackoverflow.com/questions/4238944/controlling-maven-final-name-of-jar-artifact

- add benefits and advantages about TransmittableThreadLocal
- add faq
- add 3rd party introduction articles