Use netrc for GitHub credentials

This changes the authentication mechanism from passing an authorization token / API key to using basic auth. Basic auth didn’t work when I initially tested the upload API, but hopefully GitHub has since added it (I did request it, but didn’t get a reply, so no idea if the omission was an oversight or by design).
Allow fractional font sizes.

Closes #1125
File path settings now rank higher than scope settings

A file setting like “src/*.cc” is arguably more specific (and thus more local) than targeting the scope “source.c++”, so it makes sense that the file settings rank higher than scope settings.

Some users also find it natural to target file extensions over scopes, but as TM will store some learned settings with a scope selector, it would previously lead to confusion, when a user was unable to e.g. change tab size for “*.php” (because TM had a learned setting for “source.php”).
Replace iterate macro with new for loop (C++11)

Also use emplace_back a few places.
Log error when mkdir() fails
Saving file with missing parent asks if it should be created
Improve “you are recording a macro” dialog

Rather than tell the user how to stop recording, we now offer it as an option.
Add API to get folded range for a point

This is required to show tool tips when hovering a fold marker or to unfold the fold marker clicked.
Add API to unfold a range

The function will unfold anything completely within the range that also touches one of the range’s end points.

This is because the layout will show adjoining folded ranges as a single image, so if the user clicks this, it is unclear which of the ranges to actually unfold (the layout return a range that encompass all the adjoining folds).
Clicking a folded range will now unfold it
Fix value for AXSelectedText

We were grabbing a const reference to a reference into a temporary object (result of editor_t::ranges), so the range used was effectively a pointer to a destroyed object.
Change ASSERT_NE → ASSERT

Since we do not have a to_s function defined for the iterator type, we cannot use “semantic assertions”.
Remove unneccessary #import statements
Add safeObjectAtIndex to NSArray

This is defined in OakTabBarView as a static method, but it could be useful elsewhere.
Use new safeObjectAtIndex method

Also removed the static SafeObjectAtIndex mehtod in OakTabBarView
Ensure FSItem name property is not nil when setting menu title

We use to pass nil to NSMenuItem initWithTitle: when clicking the SCMFolders in
SCM Status (see commit e5841fe); however, we will *probably* never encounter
this now. But it might be useful, if custom data sources are implemented for the
file browser in the future.
Implement accessibilityIsAttributeSettable: for all attributes

Previously if using the Accessibility Inspector exceptions could be thrown.
Show git conflicts with priority
Note that capnp is now brew installable
Fix file browser height for tabs above document

This fixes regression caused by 1de5d90475788143655a60fdbff654139fec3cb4 that
divider height and default compression priority disallowed expected height.