[filebrowser] Edit File could be in a fixed width font

When using the File Browser then Edit File, the resulting Editor does not use fixed width fonts. Space control for files and or code (E.g., like a shell script called by an Oozie job) is extremely difficult. In order to be sure that the spacing is correct the files must be copied out to another file editor then copied back. I would recommend this internal file editor be used with a fixed width font so that is not necessary.