Because some use cases cannot pass

1. the shell should not remove escape sequence \' and \" in a string.
2. `tsParseTime` should not unescape the next string token (this issue
appears after the first issue was fixed).
3. `value[4] != '-'` in `tsParseTime` crashes in rare case if `value[4]`
is in unallocated virtual memory.
4. `operator[x]` and `delimiter[x]` may result in unexcepted behavior
as string is utf-8 encoded and `x < 0` could be true.
5. changes the behavior of `tscGetToken` a little: now, unescaped single
quotation is allowed in double quoted strings and unescaped double quotation
is allowed in single quoted strings.
6. minor performance improvements and other improvements.

restful commands with length between 65380 and 65536 can trigger
this issue.

the basic idea is to change clean up procedure to 2 steps,
the 1st step only marks the time controller as to be cleaned up,
the 2nd step executes in the timer thread and does the
actual job to avoid race.

I also change `pCtrl->ticks = rand() / pCtrl->maxTicks` to
`pCtrl->ticks = rand() % pCtrl->maxTicks`, because I think
this is a typo but not sure about this.

1. fix memory leak:
`memset(&pool_p, 0, sizeof(pool_p))` sets the pointer to NULL,
so `free(pool_p)` does nothing.
2. improve performance by move some code to the outside of the lock.