Tail of a string starting from the 1st occurrrence of a given fragment
Tail = strstr(Strings, StartingFragment)
Matrices of strings, of identical dimensions.
StartingFragments can be a single string. It is then used
for all Strings components.
Tail = strstr(Strings, StartingFragment) builds and returns a matrix
of strings such that, for each element Strings(i), Tail(i)
is the part of Strings(i) starting from the first occurrence of
startingFragment(i), up to the end of Strings(i).
If StartingFragment(i) is not found in Strings(i),
Tail(i) is set to "".