[ttml10se] updated PER draft

I've made some additional editorial
fixes<http://services.w3.org/htmldiff?doc1=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fttml%2Fraw-file%2F2a6bd3632e73%2Fttml10%2Fspec%2FPER-ttaf1-dfxp-20130515-for-WG-review.html&doc2=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fttml%2Fraw-file%2F521480e5305b%2Fttml10%2Fspec%2FPER-ttaf1-dfxp-201305DD.html>[1]
in the draft PER [2][3] to dispose of some lingering comments I had in
an old mail folder, as well as improve some language after a careful review
[up through the end of Section 7]. I'm working on Section 8 to the end now,
but wanted to get this out.

Also - updated ttml-changes<http://services.w3.org/htmldiff?doc1=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fttml%2Fraw-file%2F2a6bd3632e73%2Fttml10%2Fspec%2Fttml-changes.html&doc2=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fttml%2Fraw-file%2F521480e5305b%2Fttml10%2Fspec%2Fttml-changes.html>[4]
and ran HTML tidy on this PER.

[1]
http://services.w3.org/htmldiff?doc1=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fttml%2Fraw-file%2F2a6bd3632e73%2Fttml10%2Fspec%2FPER-ttaf1-dfxp-20130515-for-WG-review.html&doc2=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fttml%2Fraw-file%2F521480e5305b%2Fttml10%2Fspec%2FPER-ttaf1-dfxp-201305DD.html
[2]
https://dvcs.w3.org/hg/ttml/raw-file/default/ttml10/spec/PER-ttaf1-dfxp-201305DD.html
[3]
https://dvcs.w3.org/hg/ttml/raw-file/default/ttml10/spec/PER-ttaf1-dfxp-201305DD.zip
[4]
http://services.w3.org/htmldiff?doc1=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fttml%2Fraw-file%2F2a6bd3632e73%2Fttml10%2Fspec%2Fttml-changes.html&doc2=https%3A%2F%2Fdvcs.w3.org%2Fhg%2Fttml%2Fraw-file%2F521480e5305b%2Fttml10%2Fspec%2Fttml-changes.html

Note: I notice the difference generator results [1][4] have some false
positive markings that are not real changes.