Common interface across the XSSF Ptg / Pxg classes

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1612149 13f79535-47bb-0310-9956-ffa450edef68
XSSF Pxgs must escape sheet names where required when generating the formula string

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1612150 13f79535-47bb-0310-9956-ffa450edef68
Change how we update sheet names in XSSF formulas and names, when renaming sheets, to take advantage of the simpler structure that Pxg now offers

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1612151 13f79535-47bb-0310-9956-ffa450edef68
Comments updates

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1612156 13f79535-47bb-0310-9956-ffa450edef68
More unit tests for #56737 and #56752

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1612157 13f79535-47bb-0310-9956-ffa450edef68