[* Duration] Extract duration units when preceded by ordinal numbers

[aitelint]

Duration units like "week", "month", "year"... should be recognized as duration entities when preceded by ordinal numbers. For example: "the first week is dedicated to exercises" --> "week" (duration)

[tellarin]

@LionbridgeCSII, can you take a stab at this and see if there may be any side-effects?

[aitelint]

@tellarin, yes there are some interferences with DatePeriod and now some patterns are not correctly handled in certain languages. I am working on fixing these issues.

[tellarin]

Please raise a flag if this becomes too unwieldy.