new [gzip-true parm will gzip traced message format on the wire

This small set of changes will allow you to add the [gzip-true command-line parameter to the intrace javagent.
Once set, the agent will gzip all trace data and the UI un-gzips the data.
By default, this parameter is set to false and the new code will never execute.

GZip implementation came from a single java source file in the public domain:  http://iharder.sourceforge.net/current/java/base64/
I added this .java to org.intrace.shared package.
This API is invoked in two places:  NetworkDataSenderThread and NetworkDataReceiverThread.

See the new junit test org/intracetest/agent/CompressionTest.java for a rough idea of precisely how much smaller the gzipped trace messages are.

I opted not to add a GUI check box for compression to keep this enhancement less complicated.
Once a client connects to the agent, it discovers whether gzip is enabled or not.  There is no switching between gzip-true and gzip-false while the connection is established.

The following details the manual testing done to verify this enhancement
############################################################################

########################################################################
## I started the example.TraceExample program using these intrace arguments:
```
java -javaagent:intrace-agent.jar=[regex-example[gzip-true example.FirstTraceExample
```
#######################################################################
## Then I connected the InTrace GUI to 9123.
## Then I get the port number of the trace connection (64097) as follows:
```
eriks-mbp:bin erikostermueller$ lsof -i | grep java
java      20652 erikostermueller   27u  IPv6 0xbe49a2b3acba2363      0t0  TCP localhost:64096->localhost:9123 (ESTABLISHED)
java      20652 erikostermueller   28u  IPv6 0xbe49a2b3adec28a3      0t0  TCP localhost:64098->localhost:64097 (ESTABLISHED)
java      20731 erikostermueller   24u  IPv6 0xbe49a2b3a4efebe3      0t0  TCP *:9123 (LISTEN)
java      20731 erikostermueller   25u  IPv6 0xbe49a2b3adec1363      0t0  TCP localhost:9123->localhost:64096 (ESTABLISHED)
java      20731 erikostermueller   26u  IPv6 0xbe49a2b3acba2be3      0t0  TCP *:64097 (LISTEN)
java      20731 erikostermueller   27u  IPv6 0xbe49a2b3a4eff023      0t0  TCP localhost:64097->localhost:64098 (ESTABLISHED)
java      20745 erikostermueller   24u  IPv6 0xbe49a2b3bb084463      0t0  TCP *:9124 (LISTEN)
java      20746 erikostermueller   49u  IPv6 0xbe49a2b3a4efe363      0t0  TCP *:9125 (LISTEN)
java      20746 erikostermueller   57u  IPv6 0xbe49a2b3a4efe7a3      0t0  TCP *:http-alt (LISTEN)
```
#########################################################################
## The above output showed me that I could trace on 64097.
## So I started the capture with this:
```
sudo tcpdump -s 0 -w myTrace.pcap -i 7 host localhost and port 64097
```
#########################################################################
## Then I displayed the capture with this:
```
tcpdump -r myTrace.pcap -X -q | more
```
#########################################################################
##  You can see the base64/gzip text below:
##  See the long string of ASCII that started with IAAAAA ?
##  That is roughly the start of the base64/gzip data
```
tcpdump -r myTrace.pcap -X -q | more

23:34:00.096086 IP localhost.64098 > localhost.64097: tcp 0
        0x0000:  4500 0034 1107 4000 4006 0000 7f00 0001  E..4..@.@.......
        0x0010:  7f00 0001 fa62 fa61 a702 c6cc 80b0 9d16  .....b.a........
        0x0020:  8010 3292 fe28 0000 0101 080a 0f2f f975  ..2..(......./.u
        0x0030:  0f2f f975                                ./.u
23:34:00.096110 IP localhost.64097 > localhost.64098: tcp 111
        0x0000:  4500 00a3 81d9 4000 4006 0000 7f00 0001  E.....@.@.......
        0x0010:  7f00 0001 fa61 fa62 80b0 9d16 a702 c6cc  .....a.b........
        0x0020:  8018 23e2 fe97 0000 0101 080a 0f2f f975  ..#........../.u
        0x0030:  0f2f f975 7400 6c48 3473 4941 4141 4141  ./.ut.lH4sIAAAAA
        0x0040:  4141 4141 4973 324d 7259 794e 7245 794d  AAAAIs2MrYyNrEyM
        0x0050:  4e41 7a73 4453 4e74 596f 326a 4c56 4b72  NAzsDSNtYo2jLVKr
        0x0060:  556a 4d4c 6368 4a31 5850 4c4c 436f 7543  UjMLchJ1XPLLCouC
        0x0070:  536c 4b54 4535 3168 5967 415a 5a4a 5443  SlKTE51hYgAZZJTC
        0x0080:  306f 7938 2f4e 3855 3073 7938 6c4f 7346  0oy8/N8U0sy8lOsF
        0x0090:  4b71 7454 4530 414f 694a 7a2f 3049 4141  KqtTE0AOiJz/0IAA
        0x00a0:  4141 3d                                  AA=
23:34:00.096134 IP localhost.64098 > localhost.64097: tcp 0
        0x0000:  4500 0034 f7a2 4000 4006 0000 7f00 0001  E..4..@.@.......
        0x0010:  7f00 0001 fa62 fa61 a702 c6cc 80b0 9d85  .....b.a........
        0x0020:  8010 328b fe28 0000 0101 080a 0f2f f975  ..2..(......./.u
        0x0030:  0f2f f975                                ./.u
```
##########################################################################
## Then, I repeated the above testing without the new gzip compression.
## I started the sample program like this:
```
java -javaagent:intrace-agent.jar=[regex-example[gzip-false example.FirstTraceExample
```
#########################################################################
## But you can also omit the [gzip parameter and you will get the same result,
## which is no gzip compression.

```
23:29:22.319488 IP localhost.64086 > localhost.64085: tcp 0
        0x0000:  4500 0034 103b 4000 4006 0000 7f00 0001  E..4.;@.@.......
        0x0010:  7f00 0001 fa56 fa55 908f 36e2 9866 4779  .....V.U..6..fGy
        0x0020:  8010 214f fe28 0000 0101 080a 0f2b c291  ..!O.(.......+..
        0x0030:  0f2b c291                                .+..
23:29:22.319502 IP localhost.64085 > localhost.64086: tcp 149
        0x0000:  4500 00c9 ca4d 4000 4006 0000 7f00 0001  E....M@.@.......
        0x0010:  7f00 0001 fa55 fa56 9866 4779 908f 36e2  .....U.V.fGy..6.
        0x0020:  8018 23e2 febd 0000 0101 080a 0f2b c291  ..#..........+..
        0x0030:  0f2b c291 7974 004a 5b32 333a 3239 3a32  .+..yt.J[23:29:2
        0x0040:  322e 3331 395d 3a5b 315d 3a65 7861 6d70  2.319]:[1]:examp
        0x0050:  6c65 2e46 6972 7374 5472 6163 6545 7861  le.FirstTraceExa
        0x0060:  6d70 6c65 3a77 6f72 6b4d 6574 686f 643a  mple:workMethod:
        0x0070:  2041 7267 2028 666f 6f29 3a20 666f 6f62  .Arg.(foo):.foob
        0x0080:  6172 7974 0042 5b32 333a 3239 3a32 322e  aryt.B[23:29:22.
        0x0090:  3331 395d 3a5b 315d 3a65 7861 6d70 6c65  319]:[1]:example
        0x00a0:  2e46 6972 7374 5472 6163 6545 7861 6d70  .FirstTraceExamp
        0x00b0:  6c65 3a65 7863 6570 7469 6f6e 4d65 7468  le:exceptionMeth
        0x00c0:  6f64 3a20 7b3a 3534 79                   od:.{:54y
23:29:22.319509 IP localhost.64086 > localhost.64085: tcp 0
        0x0000:  4500 0034 25fd 4000 4006 0000 7f00 0001  E..4%.@.@.......
        0x0010:  7f00 0001 fa56 fa55 908f 36e2 9866 480e  .....V.U..6..fH.
        0x0020:  8010 2146 fe28 0000 0101 080a 0f2b c291  ..!F.(.......+..
        0x0030:  0f2b c291                                .+..
```