Revert "remove unused methods and parameters for WEB-9022 +review WEBCR"

This reverts commit e12ef1ec4cc9eec24a01d0004663bdab4bfc4f74.
remove default values from parameters for branchTopic and inheritTopic. remove extra parameters from call to inheritTopic. Add docblock for split parameter in branchTopic. for WEB-9022 +review WEBCR-272
re-remove addToTOC, its callers, the skipTOC parameter, and the last parameter of calls to branchTopic and inheritTopic for WEB-9022 +review WEBCR-272
remove special page for WEB-9052 +review WEBCR
code conventions for WEB-9052 +review WEBCR-285
remove PonyDocsExtension::ClearNavCache() and all callers for WEB-9092 +review WEBCR. this is safe because we now call the working PonyDocsProductVersion::ClearNAVCache() as part of the TOC save hook.
code convention tax for WEB-9092 +review WEBCR-299
Merge pull request #15 from splunk/dev-WEB-9052

Remove defaults for parameters, and remove an extra parameter in method call
adding checks for topic names, per WEB-7056
adding tags to forbidden chars, per WEB-7056
adding quotes to forbidden chars, per WEB-7056
Merge pull request #16 from splunk/dev-WEB-9092

Remove orphaned and confusing PonyDocsExtension::ClearNavCache() method
Merge pull request #17 from splunk/dev-WEB-9022

Remove default values from branch methods, and remove extra parameter for one caller
Merge pull request #18 from splunk/dev-WEB-7056

Don't allow topics to be creted with illegal characters
report all errors in a single alert. factor out validation methods and encapsulate them. for WEB-7056 +review WEBCR-305
factor out event handler, and rename validator namespace for WEB-7056 +review WEBCR-305
replace constructor with a literal, and remove unnecessary parentheses for WEB-7056 +review WEBCR-305
Merge pull request #19 from splunk/dev-WEB-7056

Client-side validation to prevent creation of topic names with bad characters
merge master to branch for WEB-9040