Timer names are weird

I'm not sure if this can be changed in v2, but i trip on it every time.

| Textual description | googlebenchmark name | common(?) name | `TIME(1)` | C++ |
| ------------------------ | ------------------------------- |------------------- |-----|-----|
| the time that has passed on your usual [clock](https://en.wikipedia.org/wiki/Clock) | `Time` | `wall clock` | `real`, `Elapsed (wall clock)` | `high_resolution_clock` / `steady_clock` |
| the time spent in the main thread only | `CPU` | ? | ? | `clock_gettime(CLOCK_THREAD_CPUTIME_ID)` |
| the total amount of the time the processor[s] has spent doing something (all threads combined) | - (i miss it) | ? | `user` | `clock` |

This is really confusing, i think.