Makes VexCL work with adaptive steppers

refs #107
Provides specialization of same_instance_impl for vexcl containers

refs #110
fixes #109 by adding explicit conversions from multiprecision expression templates to numbers
Merge pull request #108 from ddemidov/vexcl-adaptive-steppers

Makes VexCL work with adaptive steppers
Merge pull request #111 from ddemidov/vexcl-same_instance

Provides specialization of same_instance_impl for vexcl containers
improving jamfile for vexcl example
Merge branch 'master' of github.com:headmyshoulder/odeint-v2
tmp commit before pull
fixing unit tests for vexcl
fix type defs for standard stepper in integrate function, fixes #109
simplified rk concept tests
added multiprecision types to rk concept tests, first part for #112
Merge branch 'master' of github.com:headmyshoulder/odeint-v2
checking bind and reference_wrapper with boost config macros
Merge branch 'master' of github.com:headmyshoulder/odeint-v2
fix some errors with intel compiler
fixing #115
Merge branch 'master' of github.com:headmyshoulder/odeint-v2
test case for #115
a few more words in iterator docs