fixed a bug that wrong calculates textfield height when the textfield has a custom font defined in font extensions

git-svn-id: http://svn.code.sf.net/p/dynamicreports/code/trunk@742 bf0c503b-2351-4f66-9eae-aa52f3279a3f
new junit test - CustomFontTest

git-svn-id: http://svn.code.sf.net/p/dynamicreports/code/trunk@743 bf0c503b-2351-4f66-9eae-aa52f3279a3f