Non-virtual phrases are a bit faster.

These ones won't have separable component tweening.
Maybe that can be done on the Sequence level to avoid virtual cost.
Template Sequence on phrase type.

Allows separable easing without virtual function call overhead
or pointer chasing for phrases.
Phrases can be tightly packed in Sequences.
Separable ease with timeline working.
Many tweens to single element benchmark.
SequenceT consistency.
MotionT consistency.
Tests for separable easing of vec2.
Separated Benchmark tests from main tests.
Reasonable set of benchmark tests.

Sample output:
Working with 10000 motions.
[Creating Motions]                                4.3ms
[Stepping Motions 1x]                             0.642002ms
[Stepping Motions 60x]                            27.705ms
[Clearing Motions]                                0.0320077ms
[Stepping Empty Timeline 60x]                     0.00101328ms
[Creating Motions from shared Sequence]           1.40804ms
[Stepping Motions with shared Sequence 1x]        0.352979ms
[Stepping Motions with shared Sequence 60x]       18.619ms

Many Targets, One Phrase Each.
[Choreograph Timeline]                            36.32ms
[Cinder Timeline]                                 50.604ms
Comparative timeline performance (Choreograph:Cinder): 0.717731
[Choreograph Timeline]                            34.441ms
[Cinder Timeline]                                 50.113ms
Comparative timeline performance (Choreograph:Cinder): 0.687266

Single Target, Many Phrases.
[Choreograph Timeline]                            1.90502ms
[Cinder Timeline]                                 222.727ms
Comparative timeline performance (Choreograph:Cinder): 0.00855318
[Choreograph Timeline]                            1.45304ms
[Cinder Timeline]                                 611.326ms
Comparative timeline performance (Choreograph:Cinder): 0.00237687
The day has arrived.
Trying to track down quaternion issue.

Doesn't make nan axes like the cinder one did.
Always normalize target quaternions.

Noted in the specialized lerp function.
Applied in the dev app.
Whitespace
Variable names.
Merge pull request #3 from sansumbrella/stack

Compile-time polymorphism for phrases, not run-time.