Remove reference to sparse boolean in javadoc

The JavaDoc referred to a sparse boolean. However, in the current method signature this is no longer present.
Allow the full spectrum of logging with freely selectable loglevel.
ECDH: try use default KeyPairGenerator/KeyFactory/KeyAgreement, fallback to BC

SunPKCS11-NSS provides ~3x speedup [19ms->6ms] in getAgreedSecret()
and ~1.6x speedup [20ms->12ms] in generateKeyPair() functions
(both are rather heavy).

Unfortunately, on java6 SunPKCS11-NSS KeyPairGenerator/KeyFactory are broken.

    [junit] java.lang.RuntimeException: Could not parse key values
    [junit] 	at sun.security.pkcs11.P11Key$P11ECPublicKey.fetchValues(P11Key.java:989)
    [junit] 	at sun.security.pkcs11.P11Key$P11ECPublicKey.getParams(P11Key.java:1014)
    [junit] 	at sun.security.pkcs11.P11ECDHKeyAgreement.engineDoPhase(P11ECDHKeyAgreement.java:94)
    [junit] 	at javax.crypto.KeyAgreement.doPhase(DashoA13*..)
    [junit] 	at freenet.crypt.ECDH.getAgreedSecret(ECDH.java:95)
    [junit] 	at freenet.crypt.ECDHTest.testGetAgreedSecret(ECDHTest.java:32)
    [junit] Caused by: java.io.IOException: Point does not match field size
    [junit] 	at sun.security.ec.ECParameters.decodePoint(ECParameters.java:75)
    [junit] 	at sun.security.pkcs11.P11ECKeyFactory.decodePoint(P11ECKeyFactory.java:61)
    [junit] 	at sun.security.pkcs11.P11Key$P11ECPublicKey.fetchValues(P11Key.java:986)

See: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6763530

Try use default providers for everything, then try fallback to
KeyFactory and KeyPairGenerator from BouncyCastle with KeyAgreement from
default provider (this combination works on java6 too, and still faster than
pure-BC), if that fails too (while previous combination works now, but using
keys and algorithm from different providers can be flaky) - fallback to
everything-from-BouncyCastle (as before).
Fix bogus length check, can be less than the maximum.
Delete now obsolete comments.
Merge branch 'stable-1448-new' into next

Conflicts:
	src/freenet/crypt/ECDH.java
ECDSA: try use default KeyPairGenerator/KeyFactory/Signature, fallback to BC

SunPKCS11-NSS provides ~5x speedup [18ms->3.3ms] in sign(),
4x speedup [25ms->5.4ms] in verify() and ~1.6x speedup [20ms->12ms]
in generateKeyPair() functions (all are rather heavy).

Unfortunately, on java6 before 1.6u37 SunPKCS11-NSS
KeyPairGenerator/KeyFactory are broken.

    [junit] java.lang.RuntimeException: Could not parse key values
    [junit] 	at sun.security.pkcs11.P11Key$P11ECPublicKey.fetchValues(P11Key.java:989)
    [junit] 	at sun.security.pkcs11.P11Key$P11ECPublicKey.getEncodedInternal(P11Key.java:999)
    [junit] 	at sun.security.pkcs11.P11Key.getEncoded(P11Key.java:111)
    [junit] 	at freenet.crypt.ECDSA$Curves.selftest(ECDSA.java:57)
    [junit] 	at freenet.crypt.ECDSA$Curves.<init>(ECDSA.java:101)
    [junit] 	at freenet.crypt.ECDSA$Curves.<clinit>(ECDSA.java:35)
    [junit] 	at freenet.crypt.ECDSATest.setUp(ECDSATest.java:21)
    [junit] 	at junit.framework.TestCase.runBare(TestCase.java:128)
    [junit] 	at junit.framework.TestResult$1.protect(TestResult.java:106)
    [junit] 	at junit.framework.TestResult.runProtected(TestResult.java:124)
    [junit] 	at junit.framework.TestResult.run(TestResult.java:109)
    [junit] 	at junit.framework.TestCase.run(TestCase.java:120)
    [junit] 	at junit.framework.TestSuite.runTest(TestSuite.java:230)
    [junit] 	at junit.framework.TestSuite.run(TestSuite.java:225)
    [junit] 	at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:422)
    [junit] 	at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:931)
    [junit] 	at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:785)
    [junit] Caused by: java.io.IOException: Point does not match field size
    [junit] 	at sun.security.ec.ECParameters.decodePoint(ECParameters.java:75)
    [junit] 	at sun.security.pkcs11.P11ECKeyFactory.decodePoint(P11ECKeyFactory.java:61)
    [junit] 	at sun.security.pkcs11.P11Key$P11ECPublicKey.fetchValues(P11Key.java:986)
    [junit] 	... 16 more

See: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6763530

Try use default providers for everything, then try fallback to
KeyFactory and KeyPairGenerator from BouncyCastle with Signature from
default provider (this combination works on broken versions of java6 too,
and still faster than pure-BC), if that fails too (while previous
combination works now, but using keys and algorithm from different
providers can be flaky) - fallback to everything-from-BouncyCastle
(as before).
Fix bogus length check in ECDSA, like 9bd78683f69917789efea38add09d3d9ade9ed52