#14 jdk 1.5 compliant

[Perry]

Just tiny changes to enable the package to be compiled
under jdk 1.5

enum is a reserved keyword for jdk 1.5, need to be
renamed it from 4 files

.getState() conflict with Thread.getState() under jdk
1.5, need to be renamed.

thus the package can be compiled under jdk 1.5. for
complete jdk 1.5 compliant, program code may need
significant changes.