Fix for https://bugs.eclipse.org/bugs/show_bug.cgi?id=149224.

When adding a ['foo'] style property in a content assist,the proposal strategy now checks to see if the preceding char is a '.' and if so, it will replace it as part of the proposal if that proposal is selected by the user.

Regression test coverage also added.

Also made a small thread sync change in JSPModelProcessor to fix a possible race condition in refresh().
diff --git a/jsf/tests/org.eclipse.jst.jsf.contentassist.tests/testdata/bug_149224.properties.data b/jsf/tests/org.eclipse.jst.jsf.contentassist.tests/testdata/bug_149224.properties.data
new file mode 100644
index 0000000..d29c89a
--- /dev/null
+++ b/jsf/tests/org.eclipse.jst.jsf.contentassist.tests/testdata/bug_149224.properties.data
@@ -0,0 +1,4 @@
+prop1_x=foo
+prop2_x=bar
+prop.with.dots_x=foo.bar
+anotherprop=blah
\ No newline at end of file