change PATH in server tests to prefer blib/script over bin

Running the tests under a perlbrew environment may fail because the
system perl does not have the requisite features/modules installed. The
tests should normally be run after blib has been populated and so
putting that in front of the PATH in these tests ensures the right
interpreter is used.
Merge pull request #15 from spacebat/master

Thanks!!!
add .gitignore and remove no exist file
add the 'loglevel' command
fixed #15
fixed #16
update test for #17
made debuglex accept file and fixed some miss
made Symbol have linenumber/colnumber
add command for exploring package
update help
made test read PLSENSE_TEST_SOURCE
update version to 0.20
fixed #18