[Minotaur] Release 0.3

[Ashutosh Mahajan]

Dear all 

We are happy to announce a new release of Minotaur. Source code is available
on GitHub (https://github.com/minotaur-solver/minotaur). Binaries will be made
available soon.

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Release Notes for Minotaur v0.3
---------------------------------------------

New features
- A new shared-memory parallel version of Quesada-Grosmann (mqgpar) with extra
  linearization schemes
- A new solver, mglob for global optimization of MIQCQPs
- New solvers moa (outer-approximation) and mlstoa (lazy cuts based
  single-tree outer-approximation) for convex MINLP using Cplex MILP solver.

Libraries, binaries and interfaces
- merged multiple source and interface related libraries into a single
  (libminotaur) library
- nl files can be written
- mps files (linear only) can be read
- C-interface with Cplex's LP and MILP solvers (CplexEngine)

Improvements and bug fixes
- several bugs fixed in the nonlinear branch-and-bound (mbnb) and
  Quesada-Grossmann (mqg) solvers
- removed all boost shared pointers; using normal pointers now
- website moved to https://minotaur-solver.github.io/

Source code
- moved the subdirectory algorithms in src/ to solvers
- consolidated interfaces to third-party software like ASL,
  LP, MILP and NLP subsolvers in src/interfaces

Third-party software
- upgraded third-party software and their dependencies

Regards
Meenarli Sharma, Prashant Palkar, Mustafa Vora, Ashutosh Mahajan and others
from team Minotaur