add support for parser keywords specifying to multiple deck keywords

Say hello to the complete set of well, region, field and group output
specifiers soon...
avoid illegal internal names in the MULT keywords

before this, the variants with the trailing minus were just silently
ignored, and even if they were not, the code generator would have
produced illegal code, because the keyword name is used for a C++
variable there, i.e. the names needed to be valid names in the C++
sense. "Happily", these the former bug canceled the latter, so the
build went through...

now, there is only one internal keyword called "MULT_XYZ" which
matches on all possible variants which are allowed in a deck. The
mechanism used is a deck name list...
use deck keyword name list for the well output specifier keywords
Merge pull request #242 from andlaus/deck_keyword_lists

Implement deck keyword lists
grid properties: add support for the NTG keyword

Whoever came up with that keyword deserves a spanking because its
semantics are adapting thickness of the grid layers using the rock
properties without modifying the grid (and thus the output is not
showing what is actually used). As I understood that whole affair,
this is also done incorrectly, because the flow is not distorted in
depth direction but this the permeability should be divided by the NTG
values as the fluids seep through the thinner layers more quickly...

Anyway, we have to implement it, so here we go.
Added new enum to enumerate the different face directions.
Added transMult container - which only returns 1.0
Added TransMult object to EclipseState
Merge pull request #244 from joakim-hove/TransMultContainer

Trans mult container
Merge pull request #245 from andlaus/add_ntg_gridproperty

grid properties: add support for the NTG keyword
Fixed trivial typo.
Typo in install target
Added SWATINIT as supported grid property.
Changed from semicolon to comma, to fix compilation failure
Merge pull request #246 from flikka/SWATINIT-semicolon-bug

Changed from semicolon to comma, to fix compilation failure
fix build

*grr* spurious comma! Though I'm wondering a bit why it compiled on my
 machine yesterday...
Merge pull request #247 from andlaus/fix_build

fix build
syncronize Findopm-parser.cmake with the opm-core version

the ERT libraries and headers were missing and a few other minor
cleanups. see https://github.com/OPM/opm-core/pull/601 for details.
add the boost::regex library as a prerequisite

this is required for regex-matching keywords. Once GCC 4.9 is the
minimum compiler version to be supported, this can be dropped in favor
of std::regex ...
add boost::regex as a prerequisite to the opm-parser build system