BUG: Fix for #1487

The parser could sometimes generate invalid code if the
source-file-comments were enabled, this moves the comments outside the
html-tag to circumvent these problems, update test as well.
DateField.js event selector regression (fixes #1528)

See 19a8545076f477d15aa5ed7fe52af020f43d28ab
Merge pull request #1726 from s-m/1487-fix-template-comments

BUG: Fix invalid code with source-file-comments, fixes #1487
removing potentially invalid html in email

The generic email template encapsulates the "body" content in a paragraph mark.  This is undesirable as it can lead to invalid HTML. Rather than using a paragraph, it is better to have a div encapsulating the content.

The underlying reason for this is that $Body is usually HTML and this can included block elements (div, p, etc...) that are not allowed within paragraphs (p).

It is important that the HTML is valid, because it will reduce the likelihood for it being marked as spam, because it is less likely to show up strange formatting and for use of tools like emogrifier.
Extended docs for shortcode handling and doctypes (fixes #1700)
Remove duplicate functionality between float and double
Merge pull request #1769 from wilr/doubleduplication

Remove duplicate functionality between float and double
Enforcing extension-less file validation (fixes #1767)

By default, File.allowed_extensions contains '' (no extension),
but if you specifically remove it, the validation should pick it up.
BUG: HiddenFields and VisibleFields should always return extraFields

HiddenFields() and VisibleFields() should always return extraFields, e.g. HiddenFields doesn't return SecurityID if it is called before Fields().
FIX We still need XML escaping on href attributes in HTML4Value
Merge pull request #1773 from silverstripe-rebelalliance/fix/htmlvalue_attr_escaping

FIX We still need XML escaping on href attributes in HTML4Value
BUG HTTP will now correctly pass over mailto: links when converting relative links to absolute (e.g. in Emails)
Include AllPages() form method to $allowed_actions
Merge pull request #1774 from SticksTucker/patch-1

Include AllPages() form method to $allowed_actions
FIX: _config/ directories are now correctly detected as modules (fixes #1762)

DO NOT MERGE: to be reviewed. Only i18n & Deprecation classes use
->getModules() as far as I can see. Given that the method still simply
returns an array of modulename => modulepath, I don't think it's really
an API change
"UploadFieldFileButtons" casting (regression from casting changes)

Caused the UploadField rows to show "[Object object]" because
it tried to pass through a PHP object to JS without string casting
(the return used to be a string).
Updated changelog, moved "statics in Page.php" to top

Its going to be a fatal error on every upgrade unless tended to,
so we need to ensure people don't overlook it in the guide.
3.1.0-beta3 changelog
Merge pull request #1768 from tractorcow/3.1-http-mail-fixes

BUG HTTP incorrectly converts mailto links to absolute urls
Merge pull request #1770 from kinglozzer/config-dir-detection-fix

FIX: _config/ directories are now correctly detected as modules (fixes #1762)