libgui|Drawable: Avoid unnecessary notifications when deleting contents

Remove the asset first from the group, then delete.
Fixed|libgui: Handling failed GLShader construction

GLShader is reference counted, which means it cannot be destroyed
unless its reference count is zero. A failed constructor must reset
the default reference held in the constructor of Counted.
libgui|GLProgram|GLUniform: Usability improvements

Easier method for building a program out of two vtx+frag sources,
using char const * to specify uniform names.
Tests|glsandbox: Setting up a simple Drawable
Fixed|libcommon: Compiler error (std::vector initializer)

Old gcc versions apparently can't figure out the type correctly.
Merge branch 'master' into ui-framework
Fixed|GLProgram: Allocate OpenGL program object

The GL program object was not allocated before shaders were attached
to it.
Tests|glsandbox: Print MVP matrix

The purple quad is now drawn successfully.
libgui|GLBuffer|glsandbox: Setting indices using a set::vector

Indexed drawing is now working.
Fixed|libdeng2|BitField: Initialize all elements to zero
Refactor|libgui|GLBuffer: QVector is better than std::vector for usability
Fixed|libgui|GLBuffer: Enable/disable the correct vertex attribute indices

The color attribute is now working in glsandbox.
Refactor|Partitioner: Separated the concept of a line segment from half-edge

It is inconvenient from the POV of the partitioner to model a finite
line segment in the plane using HEdge. Instead it is better to model
these separately (i.e., using two vertexes and without the HEdge
API semantics) internally within the partitioner.

HEdgeInfo has been remodeled into LineSegment which now references
any HEdge constructed from it. Whilst partitioning the coordinates
of line segment are now used directly with those of the associated
half-edge being updated to match.

Todo: Defer half-edges construction until BSP leaf creation time.
Todo: Cleanup.
bsp::LineSegment: Allow access-to/replacement-of vertexes via the API only
bsp::LineSegment: Work with Vertex directly; removed internal coords
bsp::LineSegment: Observe Vertex::OriginChange notifications

Removing the need for users of this class to manually update the
precalculated value cache explicitly via the API.

Todo: Defer updating the value cache until next accessed.
Bumped version numbers to 1.11
Merge branch 'master' into ui-framework
Fixed|Snowberry: Typo in profile duplication

Addons and load order were inadvertently added to the values array.
bsp::LineSegment: Encapsulated more logic/instance data

Plus more Partitioner cleanup.