add RADAR, code clean-up
fix text artifact
fix radar image rotation
restore radar alpha
unfix radar image rotation
add texRdius param in radar cb
add lat/lng to radar_cb, handle more than one radar
add black background in RADAR mode when and NODATA is off
free S52_RADAR_cb if texRadius is 0
optimise GL_LINES for symbols
code clean up, fix some compiler warning
fix build of s2gtk2
add target s52gtk2gl2, run on GLES2 (a subset of GL2.x)
del def S52_USE_DOTPITCH, add def S52_USE_GL2, fix GL target
fix UTF-8 text handling in GLES2 (freetype_gl)
add 52_USE_MESA3D in GLSL, add TTF label in s52.cfg
fix pattern in GLES2
refactor GL2/GLES2
fix target s52glx, s52gtk2 - GL1.x
fix target s52glx, s52gtk2 - GL1.x