CustomMember extends wrong class.

CustomMember was extending the wrong class to be able to reference $this->owner.

Also, changed CustomMember to MyMemberExtension to remain consistent with the initial example.
BUG ArrayList failing to respect the SS_Sortable interface
ref: CWPBUG-133
BUG Fix access to protected Session::current_session()
Fixes #3144
BUG fix listview not working with IE9

To reproduce:

1. Using IE9, go to demo.silverstripe.com
2. login
3. go to Pages
4. switch to listview
5. expand pages to get to one with pagination (e.g. Pages > Features > Listview)
6. go to next page

Expected: you go to the next page
Actual: it jumps you back to the home page

Fix: this fix passes parameters stored in the hash part of the url, which IE9 and below rely on for PJAX.
Merge pull request #3151 from IgorNadj/patch-2

BUG fix listview not working with IE9
API Fix HTTPS proxy header detection

Didn't use the de facto standard HTTP_X_FORWARDED_PROTO or the less standard HTTP_FRONT_END_HTTPS.
Removed the 'X-Forwarded-Proto', since PHP should prefix/underscore all HTTP headers before it hits $_SERVER.

References:
- https://docs.djangoproject.com/en/1.4/ref/settings/#secure-proxy-ssl-header
- https://drupal.org/node/1859252
- https://drupal.org/node/313145
- http://scottwb.com/blog/2013/02/06/always-on-https-with-rails-behind-an-elb/
Merge pull request #3152 from silverstripe-iterators/pulls/https-proto

API Fix HTTPS proxy header detection
Merge pull request #3138 from tractorcow/pulls/3.1/fix-arraylist-sorting

BUG ArrayList failing to respect the SS_Sortable interface
Merge pull request #3145 from tractorcow/pulls/3.1/fix-choose-stage

BUG Fix access to protected Session::current_session()
Merge pull request #3107 from micmania1/patch-1

CustomMember extends wrong class.
Update Zend_Locale_Format to the latest Zend version
Use php.internal_encoding instead of iconv.internal_encoding in PHP 5.6+
Update i18n.md

Corrected a mistake: to make a new locale available (in particular for use with silverstripe/translatable), i18n:common_locales needs to be updated, not i18n:common_languages.
Merge pull request #3158 from JorisDebonnet/patch-1

Update i18n.md
Merge pull request #3155 from simonwelsh/iconv_changes

Only use iconv.internal_encoding in PHP<5.6
Update simple-contact-form.md

corrects the description about the order of the arguments passed while creating Form object.
Merge pull request #3160 from sanjaymundhra/patch-8

Update simple-contact-form.md