Update Referece [2] to the latest version

Update the reference to the SLP Proxy-1 Blue Book and add a refeence to the new Section Control Blue Book

Replace the abbreviation "Proxi-1" with the full name of the standard "Proximity-1"

Jorge suggested to remove the note in section 3.3.2.3, but since it was already there I preferred to keep it. Can be addressed in Agency Review if needed.

In section 3.3.3.2.1 there was a wrong reference to secion 3.3.3.2 while the correct section to reference was 3.3.2.2

In section 3.3.3.2.2 Jorge suggested to add a note with reference to 3.3.2.3b (integer number of octets). An exact number of seconds will in general not 
be possible if there has to be an exact number of octets. The following Note was added:
NOTE – In case of LDPC, the acquisition sequence must be composed of an integer number of octets, as specified in section 3.3.2.3b.

In section 3.3.4.2.1 there was a wrong reference to secion 3.3.3.2 while the correct section to reference was 3.3.2.2

In section 3.3.5.2.1 there was a wrong reference to secion 3.3.3.2 while the correct section to reference was 3.3.2.2

In section 3.4.2.2 Jorge suggested to combine the 3 notes in a single note with two subnotes. Trying to apply the comment I had the impression that 2 subnotes
seems quite similar to 3 separated notes so I keept the original structure with 3 separated notes. Can be addressed in Agency Review if needed.

Update Figure 3-2 so that it says "Physical Layer" insteas of "Ph. Layer"

Change the style of the title of Section 3.4.4, 3.4.5 and 3.4.6 so that now k and n are lower case