| Parse dive plan specification. Dive plan specification string is a space separated list of dive run
time and depth values. For example dive plan 
1:00      |    10    | 12:20     |    21    | 18:30     |    21    | 40:00     |     5    | 43:00     |     5    | 45:00     |     0    | is represented by string as follows: 
1:00,10 12:20,21 18:30,21 40:00,5 43:00,5 45:00,0
 which can be described as Run time can be specified in 
seconds, i.e. 15, 20, 3600minutes, i.e. 12:20, 14:00, 67:13 Depth is always specified in meters. Dive plan specification is returned as iterator of runtime and depth
pairs is returned. Returned runtime is always in seconds since start
of a dive. Depth is specified in meters. 
    Parameters:
        spec- Dive plan specification string. |