Use k-calling string context sensitivity

This is an alternative to k-object-sensitivity that is also quite
useful in practice.
Merge branch 'java-source-analysis'

Conflicts:
	edu.illinois.jflow.wala.core.ui/src/edu/illinois/jflow/wala/utils/EclipseProjectAnalysisEngine.java
Detect static method calls more precisely using Dispatch enum

Previously the checks only check for no actual parameters. But that is
not valid since sometimes for a static method you can have actual
parameters. If you really want to check for static method, you should
check its dispatch.
All static methods return Everywhere.EVERYWHERE context

This makes it easier for reasoning. It's also the default that
Milanova did for her work on k-object-sensitivity.
Use AstJavaModRef for analysis since we are doing source analysis

See #24.
Clean up text and change layout for Wala PDG

SEe #28.