fix warning flags for test & release build

add:
 -W -pedantic -Wcast-qual -Wcast-align -Wwrite-strings
 -Wconversion -Wfloat-equal -Wpointer-arith
fix warning with -Wconversion in World class
fix warning with -Wconversion in Robot class
fix warning with -Wconversion in SquareObstacle class
fix World#getEdge() => World#getEdgeList()
fix to build with clang in Travis CI
fix warning with -Wextra-semi

With
 - Action class
 - DistSensor class
 - Obstacle class
 - MockObstacle class
 - MockWorld class
add under-score '_' to the end of data member names in Obstacle class

in
 - Obstacle class
 - SquareObstacle class
 - MockObstacle class
add under-score '_' to the end of data member names in World class

in
 - World class
 - MockWorld class
add under-score '_' to the end of data member names in Geo::Line class
add under-score '_' to the end of data member names in Robot class
add under-score '_' to the end of data member names in Action class
add under-score '_' to the end of data member names in DistSensor class

in
 - VirtualDistSensor
 - MockDistSensor
add under-score '_' to the end of data member names in Behavior class

in
 - CrashAvoidBehavior class
 - GoStraightBehavior class
fix to use latest subsumption library(for failure with release build)
fix to extract warning as error
Merge pull request #15 from cad-san/fix-build-fail-with-clang

Build Fail with clang