Feautre/#14

[timber-they]

Extend documentation -> add example and info on getting help for issue #14. Example:

./cminject.sh \
    -n 10000 \
    -D 3 \
    --x G[0,0.00052] \
    --y G[0,0.00052] \
    --z 0 \
    --vx G[0,10] \
    --vy G[0,10] \
    --vz G[1860,20] \
    --m 1.412436264e-25 \
    --J D[0,0] \
    --M D[0,0] \
    -t 0 2e-3 \
    --dt 1e-6 \
    -e test/example_field.h5 \
    -s test/pyrrole-water.molecule \
    -o results.h5 \
    --Boundaries S[0,0,0.065,0.0015,0.002] \
                 S[0,0,0.30172,0.00075,0.002] \
                 S[0,0,0.53613,0.00075,0.002] \
                 K[0,0.511,-1,0.002] \
                 C[-0.00198571,0.00198571,-0.00398571,0.00198571,0.34572,0.49972,0.002] \
    -d 0.71247 \
    --Solver RK4