Implement boolean reductions for zero-sized objects
(grafted from 84968ffff4977f02f9bd9dcbb1e7cd6243beadfd)

--HG--
branch : 3.2
extra : source : 84968ffff4977f02f9bd9dcbb1e7cd6243beadfd
fix overflow and ambiguity in SparseLU memory allocation
(transplanted from bce1ce1adff3fbd938282dea259550a3ce401414)

--HG--
branch : 3.2
extra : transplant_source : %BC%E1%CE%1A%DF%F3%FB%D98%28-%EA%25%95P%A3%CE%40%14%14
Workaround fixing aliasing issue in x = SparseLU::solve(x)
(transplanted from 24588a2fdcfa93b66557ba6711c5390847bfdf36)

--HG--
branch : 3.2
extra : transplant_source : %24X%8A/%DC%FA%93%B6eW%BAg%11%C59%08G%BF%DF6
Fix FullPivHouseholderQR ctors for non squared fixed size matrix types
(grafted from 5d557a6213f4a05e9bd06904edb5fa5fab519b80)

--HG--
branch : 3.2
extra : source : 5d557a6213f4a05e9bd06904edb5fa5fab519b80
Fix bug 708: add placement new/delete for array
(transplanted from a44c47417c2319d737b8b99bb22dfae276a9757f)

--HG--
branch : 3.2
extra : transplant_source : %A4LGA%7C%23%19%D77%B8%B9%9B%B2-%FA%E2v%A9u%7F
Fix Bug 609: Euler angles are in Range [0:pi]x[-pi:pi]x[-pi:pi].
Now the unit test verifies this (also that it is bijective in this range).

--HG--
branch : 3.2
extra : source : 42e011583bceb055a43fa688622e828fbbabf818
Fixed and simplified Matlab code and added further block-related examples
(transplanted from 2e597973fede8cd01abefd5857d1dc2b6a01371e)

--HG--
branch : 3.2
extra : transplant_source : .Yys%FE%DE%8C%D0%1A%BE%FDXW%D1%DC%2Bj%017%1E
Added optional run-time size parameters to fixed-size block methods

--HG--
branch : 3.2
Fixed typos in comments
(transplanted from 18b3820a978625853e59d172920550089e7e7fcb)

--HG--
branch : 3.2
extra : transplant_source : %18%B3%82%0A%97%86%25%85%3EY%D1r%92%05P%08%9E%7E%7F%CB
Merge with 99cb7ec9845b3e44738aa6300c880c5ae7f6d621

--HG--
branch : 3.2
QuaternionBase::slerp was documented twice and one explanation was ambiguous.
(grafted from 43047fa7fb05e571cf01cdfecd1ed7afee3b96df)

--HG--
branch : 3.2
extra : source : 43047fa7fb05e571cf01cdfecd1ed7afee3b96df
Port unsupported constrained CG to Eigen3
(grafted from 387c04265505096fb9051d9c10408a3700c258ae)

--HG--
branch : 3.2
extra : source : 387c04265505096fb9051d9c10408a3700c258ae
Remove useless register keyword

--HG--
branch : 3.2
Fix Bug 730: Path of OpenGL headers is different on MacOS
(transplanted from 358d83a0c27f44f2c3e4093c0220c06df264765b)

--HG--
branch : 3.2
extra : transplant_source : 5%8D%83%A0%C2%7FD%F2%C3%E4%09%3C%02%20%C0m%F2dv%5B
Fix bug 736: LDLT isPositive returns false for a positive semidefinite matrix
Add unit test covering this case.
(grafted from b7308ae775bbe8f1d0fd13dd60de00d09fdcaf11)

--HG--
branch : 3.2
extra : source : b7308ae775bbe8f1d0fd13dd60de00d09fdcaf11
Added examples for casting, made better examples for Maps
(transplanted from 90f8b868e6e24a198168502402e05fba06b6f652)

--HG--
branch : 3.2
extra : transplant_source : %90%F8%B8h%E6%E2J%19%81hP%24%02%E0_%BA%06%B6%F6R