and barycentric coordinates.  This is easy because we know the
number of element corners at compile time (I currently don't
see support for non-simplex elements at all).  This saves 
time, but not much: about 1%.

[[Imported from SVN: r7550]]

[[Imported from SVN: r7426]]

[[Imported from SVN: r7424]]

remove projection onto tangent space.  Is the variations are all tangent to the manifold you don't actually need it

[[Imported from SVN: r7422]]

[[Imported from SVN: r7391]]

[[Imported from SVN: r7390]]

Be smarter about when to compute what.  This speeds up assembly of the Hessian for harmonic maps from R^3 to S^2 by a factor of 3

[[Imported from SVN: r7389]]

[[Imported from SVN: r7388]]

Remove class specializations.  The old implementation for the UnitVector class will handle all cases

[[Imported from SVN: r7380]]

[[Imported from SVN: r7379]]

[[Imported from SVN: r7378]]

[[Imported from SVN: r7374]]

Remove a few specializations.  From now on we will assume that all target spaces can be parametrized by some sort of global embedding.  I don't see a case coming where that is not general enough

[[Imported from SVN: r7373]]

[[Imported from SVN: r7338]]

[[Imported from SVN: r7312]]

[[Imported from SVN: r7176]]

[[Imported from SVN: r7174]]

[[Imported from SVN: r7089]]

[[Imported from SVN: r6718]]

[[Imported from SVN: r6499]]

[[Imported from SVN: r6452]]

[[Imported from SVN: r6209]]

[[Imported from SVN: r5996]]

[[Imported from SVN: r5995]]

[[Imported from SVN: r5994]]

[[Imported from SVN: r5992]]

[[Imported from SVN: r5989]]

[[Imported from SVN: r5988]]

[[Imported from SVN: r5986]]

Compute the local corrections in local coordinates on the tangent bundle now, instead of using the embedding in the surrounding space

[[Imported from SVN: r5985]]

[[Imported from SVN: r5966]]

[[Imported from SVN: r5965]]

For this now the TangentVector class of S^n has only n components,
while the EmbeddedTangentVector class still has n+1.
The code around it needs to be fixed accordingly.

[[Imported from SVN: r5963]]

[[Imported from SVN: r5947]]

[[Imported from SVN: r5941]]

[[Imported from SVN: r5931]]

[[Imported from SVN: r5808]]

[[Imported from SVN: r5806]]

[[Imported from SVN: r5790]]

[[Imported from SVN: r5789]]