Fixed talk list item size issues.

 Some devices displayed incorrect item height. Fixed by setting both the layout_height and minHeight attributes.
Skeleton for master detail flow.

- Separated TalkListPagerFragment from MainActivity
- TalkListFragment calls the parent activity when a talk has been clicked
- Created master-detail layout for devices with 600dp width (should be ~7")
Remove speakers when updating TalkDetailFragment.

The details fragment would not clear the list of speakers in master-detail mode.
Show a placeholder in empty talk details fragment.

Instructs the user to select a talk from the list.
Retain instance of details fragment.

Keeps the fragment content across orientation changes, instead of displaying the placeholder text.
Tweaked talk list item layout.

- Use fixed margins instead of adapting to screen size.
- Removed the favorite button when in master-detail mode.
Merge branch 'master' into master_detail

Conflicts:
	src/main/res/layout/list_item_talk.xml
Fixed margins in talk details header.

Favorites button was not marginalized using the screen size dependent dimen value.
Show selection indicator in talk list.

Small fliebeltje on the right of the view is visible for highlighted views. The ListFragment keeps track of which view is currently selected because apparently the default "setSelected" method does not apply for list items.
Make sure the talk location label is single line.

Messes up the list item layout when is very little room.
Fixed crash on orientation change.

The main activity got confused when the details fragment used to be visible but is no longer accesible when the screen orientation changed. Fixed by introducing LayoutUtils helper.
Store highlight status in talk model instead of view.

Storing it in the view causes issues with reusing list item views.
Increased master-detail width selector to w720dp.

The original w600dp is too narrow for the very long titles of some of these talks.
Decreased extra margins width selector to w600dp.

The original w820dp was too restrictive: these wall-of-text abstracts need all the help they can get.
Merge pull request #9 from xebia/master_detail

Master detail